1. Field of the Invention
The present invention relates to chemical dispensing sprayers and, in particular, to aspiration-type sprayers that use a relatively large amount of carrier fluid for dispensing a relatively small amount of a chemical solution.
2. Description of the Related Art
Every year consumers apply thousands of gallons of chemicals such as fertilizers or pesticides to plants, lawns, flowers, vegetable gardens and other organic type vegetation. Typically, such chemicals are sold in plastic containers in a concentrated form. While in this concentrated form, the chemical is extremely hazardous to the consumer end user and the environment in general. Accordingly, the container typically includes an aspiration-type sprayer head assembly. An aspiration-type sprayer uses a relatively large amount of carrier fluid, such as water, to withdraw, dilute and dispense a relatively small amount of chemical from the container. To further prevent harm to the consumer, the container and the sprayer head assembly are preferably disposed of after the container's contents are exhausted. It is therefore desirable to provide a sprayer head assembly that is sufficiently low cost so as to allow the entire unit to be discarded and yet reliable and safe.
In some applications, it is desirable to use a sprayer head assembly to selectively apply the chemical/carrier mixture and the carrier fluid to a surface. For example, the chemical/carrier mixture may form a cleaning solution, which is rinsed away by the carrier fluid. Such a sprayer head assembly is particularly useful for cleaning surfaces that cannot be physically reached by the user but can be reached by the spray generated by the sprayer head assembly. U.S. Pat. No. 5,595,345 describes one such sprayer head assembly. However, this sprayer assembly includes a relatively large number of parts and is difficult to manufacture and to assemble. U.S. Pat. No. 3,940,069 describes a sprayer head assembly that is capable of forming two different ratios of a chemical/carrier fluid mixture. However, this sprayer head assembly also includes a relatively large number of parts and is difficult to manufacture and assemble.